Solid cast high performance detergent-containing articles which can be used in institutional dishwashing machines and industrial washing machines at high water temperatures are known in the art. The advent of such high performance products was stimulated in part by increased aesthetic and sanitary standards and a demand for shorter wash times. Such high performance products are generally complex detergent compositions which are hazardous to the user. High performance solid detergents generally possess a high alkalinity (e.g., greater concentrations of sodium hydroxide)--higher even to the point of posing safety hazards to the user.
High temperature, high performance solid cast detergent compositions typically contain high concentrations of alkali metal hydroxides. In addition to alkali metal hydroxides (e.g., sodium hydroxide), chemicals used in high temperature, high performance products, particularly for hard surface cleaning (e.g., warewashing) include phosphates, silicates, chlorine-containing compounds, defoamers and organic polyelectrolyte polymers. See U.S. Pat. No. 3,166,513, issued Jan. 19, 1965 (Mizuno et al); U.S. Pat. No. 3,535,285, issued Oct. 20, 1970 (Sabatelli et al); U.S. Pat. No. 3,579,455, used May 18, 1971 (Sabatelli et al); U.S. Pat. No. 3,700,599, issued Oct. 24, 1972 (Mizuno et al); and U.S. Pat. No. 3,899,436, issued Aug. 12, 1975 (Copeland et al). The alkali metal hydroxides in these compositions are very effective in removing most stubborn food soils, but a source of available chlorine is usually included to control food stains, such as tea and coffee stains. The defoamer is usually included to control foam created by a proteinaceous soil and saponified fats. The use of chlorinated cyanuarates as a source of available chlorine in detergents used to clean hard surfaces is disclosed in U.S. Pat. No. 3,166,513, issued Jan. 19, 1965 (Mizuno et al); U.S. Pat. No. 3,933,670, issued Jan. 20, 1976 (Brill et al); U.S. Pat. No. 3,936, 386, issued Feb. 3, 1976 (Corliss et al).
A problem of these high temperature, high performance solid cast detergent-containing articles, however, in addition to their high alkalinity which poses hazards to users, is their reduced effectiveness at low water temperatures. The high alkaline compositions of the prior art, while effective at high water temperatures, typically experience a reduced effectiveness at water temperatures below about 140.degree. F., necessitating the use of a large amount of detergent composition in order to obtain satisfactory cleaning results.
At high water temperatures, sodium hydroxide will effectively solubilize protein and saponify fats. At low water temperatures, however, the cleaning power of sodium hydroxide can be reduced depending on soil load and type.
A need therefore exists for a solid cast detergent composition which is effective at water temperatures below about 140.degree. F. which minimizes hazards to the user, and which does not require a large product usage level.